Elastic fluid turbine plant



Nov. 22, 1932.

A. LYSHOLM ELASTIC FLUID TURBINE PLANT Filed Sept. 6. 1927 2 sheets-,sheet 1 Patented Nov. 22, '1932 UNITED l STATES 1 PATENT OFFICE ALI LYSHOLI, Ol' STOCKHOLM, SWEDEN, ASSIGNR I10 .AKTIEBOLAGET NGSTRIS ANGTUBBIN, F STOCKHOLM, SWEDEN, A'CORPOBATION ELASTIC FLUID TUBBINE PLANT Application med September 6,' 1927, Serial No. 217,663, and in Sweden September 7, 1988.

The present 'invention relates to lelastic fluid turbine plants and has particular reference to turbo electric plants in, which the prime mover is divided into a plurality of separate sections operatin at different pressures. Still more particulrly the linvention relates to a turbine lant usingas the low pressure section a radial flow turbine of the so-called Ljungstrm type.

The Ljungstrmtype of radial flow turbine is particularly well adapted for use as a low pressure section since lwith this type it is possible to handle large volumes of steam with a turbine of small size, and to usefully extract a relatively large lquantity of heat lfrom the steam. This-type of turbine, however, if it is to be operated etliciently, must be supplied with steam at comparatively low pressure since a high initialpressure results l in leakage. in the turbine, which materially reduces the eiciency. Furthermore, the

. radial new type of turbine requires rather eiabcrate packing means to prevent steam leakage in the turbine and the use of'a low initial ressure is desirable to enable relatively snnple packing means to be employed.

Modern power plants utilize steam at high initial pressures, and in order to make use of the radial How type ofl turbine some other type of turbine must be employed to reduce the pressure of ,the lsteam fromvits initial pressure to one suitable for use in a radial flow turbine.

It'has heretofore been roposed to use an impulse type of axial ow` high pressure tur ine exhaustingto a low pressure lradial ow turbine, but this arran ement is not wholly satisfactory for use with high steam pressures because 'of the inherent limitations of the impulse type' of turbine. c

In order to secure the desired eiciency of the. plant asa whole, it is highly desirable to extract as much heat as ispossible from the steam in the hi h pressure stage or stages 'ahead of the ra- 1a1 flow turbine. This can- 4 not be done eiciently with an impulse type turbine, since this type of turbine requires y high steam velocities land high blade speeds,

which in turn involves either extremely high wheels, or both. Consequently, steam cannot be admitted in a turbine of this type around the entire periphery of the turbine wheel,

which limits the eiiiciency obtainable, and the eiliciency in such cases is also further adversely affected by high exit velocities of the steam from the turbine blades.

In accordance with the present invention,

l improve upon the'turbine arrangements heretofore Aknown by dividing the turbine plant into a low pressure section comprising a radial flow turbine of the Ljungstrm type,

and a section of higher pressure comprising one vor more turbines which are of the axial flow combined type, that is, of the type in which both impulse and reaction blading is used. By employing a turbine of the combined type ahead of the radial How turbine, I am enabled to expand high pressure steam lto a pressure suiciently low so that the operation of the radial flow turbine is material ly improved. In order tosecure the maximum eiiiciency from the combined turbines forming the section operating at high pressure I prefer to provide such turbines with rotors having at least one impulse wheel and atleast three reaction wheels. The use of the one impulse wheel permits an initial reduction in steam pressure in an eiicient manner, since the total Areduction in pressure through the impulse wheel is relatively small, while the reaction wheels provide the means for eiiiciently expanding the steam to the degree desired in this section of the apparatus.

,In accordance with the invention, the section of higher pressure may consist of a single turbine, but -in order. to secure the .most ecient design bothfrom the standpoint of thermo-dynamics and also from the standpoint of space and mechanical considerations, I- prefer to divide the higher pressure In es cases where the higher pressuresection is divaided into two separate turbines', these turbines should be designed to 'give approximately the same power output.

59 turbine or large diameters of turbine The invention is illustrated by way of example in the following drawings in'which Fig. l shows an assembly or a turbine plant;

' Fig. 2 a section on an enlarged scale through a part or the low pressure section ot the turbine plant, and lig. 3 is a section also on an argedscale of a turbine unit comprising part of the higher pressure section oil the plant. 4

rllhe low pressure section of the plant consists of av radial dow turbine designated enerally at L and comprises two turbine discs 30 and 3l' (see llig. 2) rotating in opposite directions, said discs being secured respectively to shafts l and ll. Electric generators (Gl and G aremounted on shafts l0- wit gear l2 and shaft l5 carries a gear l'l' r with gear i3.

lll and are driven respectively by S am'alturbines H and H". These turbines, inthe embodiment illustrated, comprise the section oi higher pressure ot the turbine plant and in the specic torna shown are or the combined type.

The rotor of turbine H comprises a blade ring 18- of the impulse type and three blade rings 20 of the reaction type. Turbine Hf' is of similar construction, comprising a` rotor having a blade ring 19 of the impulse :j: g.-

and` three blade rings 2l et the reaction type. lil designates 'an electrical machine for the excitation ot the generators G and G1.

Illhe steam'enters the turbinel plant from the steam supply conduit and ,passes through the'conduit 26 to the inlet of the turbine H, *from the outlet ot which it Hows through the conduit 2'? to the et of the turbine H1. From the outlet of the latter turbine the steam ldows through the'conduit 28 and through 'the branch conduits 29 to the :vo turbine of the low pressure turbine.

.llhe Stearns-Hows through the low pressure sectionof the turbine plant hrst radially and then am'ally as indicated by the 'arrows in Figf 2, and nally passes to the condenser. A Y

ln the embodiment shown, the initial pressure rofthe steam in the diderentuturbines may, for example be '35 kilograms in front of' .the high pressure part H, ld kilograms in front of the medium prbssure part/Hl and 5 lrilogramsin front of the low pressure part L, the steam in the high pressure part H then being subjected to a fall of heat of about units ot heat per kilogram, .whereas in the medium' pressure part H1 the fall of heat '.lilrewise amounts to 50 unitsv ot heat per kiloassente gram, and in the low essure part L to about 160 units of heat per ogram.

)Because ot the fact that in accordance with the present invention the type of turbine utilized in the section of higher pressure permits of a lhigh pressure drop therein, the radial ow low pressure section may be oonlstructed for a lower initial pressure and consequently the construction ot this latter sec tion may be considerably simplied from a mechanical standpoint. lis-previously stated, the radial flow typl of turbine re uires rather elaborate pac ng, usuall o the labyrinth type, and with a. low initial pressure in this turbine a relatively simple labyrinth packing may be' employed and with a relatively simple structure, steam lealra e' within the turbine, resulting in lowered il ciency thereof, may be reduced to a l lig. 2 shows the low ressure section L as comprising the two tur ine discs 30 and 3l having inter-meshing blade rings and rotating in opposite directions, said discs bein overhung on the shafts lO'and 11, and eac containing radiaLHow blades 32 and axial .flow blades 33.l I v As will vbe a parent from the drawings it l has been possi le to simplify the pac between the rotating discs 30 and 3land the adjacent fixed parts, and in contrast to the previously @own forms or construction it as been possible to make the packin such, for example, as those shown at 34, in t e form of stationar rings of conical section between which and t e rotating discs there isrprovided the usual form oi relatively simple labyrinth packin Likewise, it has been posslble to simpliigy other packings and details of construction in the turbine withoutincurring leakage sucient to impair the high value of eciency of the turbine. n v

What l claim' as new and desire to secure by Letters Patent ot the United States `ot America is a l. ln a turbine plant, in combination, va low pressure section comprising a radial dow turbine including a rotor, a section of higher pressure than the lowA pressure section-comprising an axial iowturbine havin a rotor lncludlng reaction wheels' couple rotor of the radial ilow turbine, means to supply elastic iuid to said higher pressure section to expand therein and to exhausttherefrom and means for conducting the expanded duid to said low pressure section for further expansion in the low pressure section.

2. ln a turbine plant, Ain combination, a low pressure section comprising a radial How turbine having'two shaftsv adapted to rotate v in opposite dlrections, asection of higher pressure than. said low ressure section adapted to receive motive uid at relatively high pressure and to exhaust it at relatively low pressure comprising. two axial dow turbines having reaction wheels, each of'said to the shafts having' one of said axial iow turbines connected thereto, means to supply elastic uid to" said higher pressure section to expand therein and to exhaust therefrom, and means for conducting the expanded Huid to said low pressure section for further expansion in the low pressure section.

v3. In a turbine plant, in combination, a low pressure section comprising a radial flow turbine having two shafts adapted to rotate in oppositel directions, a section of higher pressure than said low pressure section comprising a first axial iiow turbine of the type having both an impulse and reaction bladin coupled to one of said shafts and a se-con axial flow turbine of the type having both an impulse and reaction blading coupled to the secondof said shafts, means to supply elasticl fluid to said higher pressure section to expand therein and to exhaust therefrom,

and means for conductingthe expanded fluid to said low pressure section for further expansion in the low pressure section.

4'. In a turbine plant, in combination, a low pressure section comprising a-radial flow turbine having two shafts adapted torotate in opposite directions and a turbine wheel mounted on the inner end of each of said shafts, a section of higher pressure than said low pressure section comprising a first turbine connected to the outer end of one of said shafts and a second turbine connected to the outer end of the second of said shafts, means for taking power'from each of said shafts, means to supply `elastic fluid to said higher pressure section to expand therein i and to exhaust therefrom, and means for conducting the' expanded Huid to said low pressure section for further expansion in the low pressure section.

y5. In a turbine plant, in combination, a

low pressure section comprising a radial flow turbine h aving two shafts adapted to rotate in opposite directions and a turbine wheel mounted on the inner end of each of said shafts, a.' section of higher pressure .than said low pressure section comprising` a first turbine connected to-the outer end of one of said shafts and a second turbine connected to the outer end of the second of said shafts,

' means for taking power from each of said shafts, and means for connecting said first turbine,said second turbine and said radial fiow turbine-in series with ,respect to iiow of motive iuid in the order named. n

6. In a turbine plant, in combination, a

low pressure section comprising a radial flow turbine having two shafts adapted to rotate in opposite directions and a turbine wheel mounted on the inner end of each of said shafts, a section of higher pressure than said low pressure' section comprising a first' axial iow turbine having reaction wheels connect- VV.edtotheouter end of one of said shafts and a second axial Vflow turbine having reaction l l wheels connected to the outer end of the secfrom each of said shafts, means to supply elastic fluid to said higher pressure section to expand thereinand to exhaust therefrom, and means for conducting the expanded fiuid to said low pressure section for further expansion in the low pressure section.

7. In a turbine plant, in combination, a low pressure section comprising a radial How turbine having two shaft-s adapted to rotate in opposite directions and a turbine wheel mounted on the inner end of each of said shafts, a section of higher pressure than said low pressure section comprising a first axial iow turbine of the type having both impulse and reaction blading connected to the outer end of one of said shafts and a second axial flow turbine of the type having both impulse and lreaction blading connected to the outer end of the second of said shafts, means for taking power from each of said shafts, means to supply elastic fluid to said higher pressure section to expand therein and to exhaust therefrom, and means for conducting the expanded fluid to said low pressure section for furtherexpansion in the low pressure section.

8. In a turbine plant, in combination, a low pressure section comprising a y radial flow turbine having two shafts adapted to rotate in opposite directions, a section of higher pressure thanisaid low pressure section* comprising a first axial flow turbine having reaction wheels coupled to one of said shafts and a secbnd axial iiow turbine having reaction wheels coupled to the second of said shafts, and means for connecting the first axial flow turbine, the second axial flow turbine and the radial owturbine in series with respect to flow of motive fluid in the order named.

9. In a turbine plant, in combination, a low pressure section` comprising a radial flow turbine having two shafts adapted to rotate in opposite directions, a section of higher pressure than said low pressure section comprising a first axial iiow turbine having reaction wheels geared to the first of said shafts and a second axial fiow turbine having reaction wheels geared to the second of said shafts, said first and` second axial flow turbines being of substantially equal power output, and means for connecting the first axial flow turbine, the second axial flow turbine and the radial flow turbine in series with respect to ow of motive iiuid in the order turbine having two shafts adaptedto rotate in opposite directions and a turbine` wheel mounted on the inner end of each of said shafts, a section of higher pressure than said low pressure section vcomprising a first axial iow turbine having ,reaction lwheels geared.

l Lesser@ to the outer end of one of said shafts and a second axial How turbine having reaction wheels geared to the outer end of the second of said shafts, means for taking power from. each of said shafts, and means :for connecting the first axial flow turbine, the secood am'al How turbine and the radial flow -turbine in series with respect to low of motive Huid in the order named. Y A 11, ln a turbine lplant, in combination, a 10W pressure section'comprising a radial How turbinehaving two shafts adapted to rotate in opposite directions and a turbine Wheelmounted on the inner end of each of said shafts, a section of higher pressure than said 10W pressure section comprising a iirst axial How turbine of the type having both impulse and reaction blading connected to the outer end of one of said shafts and a second axial iiow turbine of the type having both impulse and reaction blading connected to the outer end of the second of said shafts, means for taking power from each of said shafts, and means for connecting the first axial loW turbine, thesecond axial flow turbine and the radial flow turbine in series with respect to the flow of motive fluid in the order named. l ln testimony whereof l ax my signature;

ALF LYSHLM. 

